The invention relates to a protective device for a driveshaft, especially a universal-jointed driveshaft. The driveshaft has two universal joints and a telescopic connecting shaft which connects the joints along a longitudinal axis. Each universal joint has a protective cone and protective tube. The protective tubes are arranged between the cones and are connected to one another in a rotationally fast way. The tubes are displacable inside one another along the longitudinal axis. One of the protective cones and one protective tube are rotatably and axially immovably secured to a universal joint. A first securing means is at the first protective cone and is rotatably connectable to a second securing means intended to be fixed to the stationary part of a machine or a similar component.
Protective devices are preferably used in connection with universal-jointed driveshafts which are used for driving agricultural implements via the power take-off shaft of the tractor. At one end, the devices are connectable to the power take-off shaft of the tractor and, at the other end, are secured to a driving journal of the implement. The protective device protects the rotating driveshaft from being touched. The protective device can be connected to a fixed point of the implement, for example. However, it is also known to provide one of the protective cones, at its free end, with a flange. Circumferentially distributed securing journals provided with undercuts axially project from the flange.
The securing journals engage a slot in a securing element which is connectable to the implement. Furthermore, the securing element has a cone-shaped portion which is used for pre-centering the flange of the protective cone. The cone-shaped portion changes into a cylindrical portion where the flange of the protective cone is centered. In this way, the securing journals projecting from the end face are guided towards the corresponding openings in a radially extending wall of the securing element. After the securing journals are positioned so as to extend through the corresponding slots, the securing operation is effected by rotating the protective cone.
A disadvantage of this design is that handling the device is complicated because from the operation position it is practically impossible to see whether the securing journals are engaged. Furthermore, it is necessary to first find the rotational position which has to be assumed by the protective cone with the securing journals relative to the slots. It is not possible to be sure that locking has actually taken place. This is due to the resilience of the protective cone in the axial direction. Thus, the actual engagement of the securing journals cannot be identified.